Receiver with t-slot opening for a slide block



Oct. 16, 1962 H. D. ALLYN 3,058,399

RECEIVER WITH T-SLOT OPENING FOR A SLIDE BLOCK Filed Dec. 14, 1959 5 Sheets-Sheet l INVEN TOR.

v ATTOQN EY Oct. 16, 1962 H. D. ALLYN 3,053,399

RECEIVER WITH T-SLOT OPENING FOR A SLIDE BLOCK Filed Dec. 14, 1959 5 Sheets-Sheet 2 Ewk E NEW EQEI E Oct. 16, 1962 H. D. ALLYN 3,058,399

RECEIVER WITH T-SLOT OPENING FOR A SLIDE BLOCK Filed Dec. 14, 1959 5 Sheets-Sheet 3 H. D. ALLYN Oct. 16, 1962 RECEIVER WITH TSI .OT OPENING FOR A SLIDE BLOCK Filed D60. 14, 1959 5 sheets-sheet 4 I; VEN TOR. ia/m1/7//9w, By my AT TOQN EY Ill I I l IIIlIl Oct. 16, 1962 H. D. ALLYN 3,058,399

RECEIVER WITH T-SLOT OPENING FOR A SLIDE BLOCK Filed Dec. 14, 1959 5 Sheets-Sheet 5 IN VENTOR.

ATTORNEY United States Patent Ofi ice 3,058,399 Patented Oct. 16, 1962 3,058,399 RECEIVER WITH T-SLOT OPENING FOR A SLIDE BLOCK Harold D. Allyn, 10 Sumner Ave., Springfield, Mam. Filed Dec. 14, 1959, Ser. No. 859,431 5 Claims. (Cl. 89--191) This invention is directed to new and useful improvements in a firearm of the autoloading, jet piston type which comprises a minimum number of component parts, none of which are objectionably small and/or intricate, the plurality of which may be economically made from stampings or screw machine stock, and all of which are of an adequate configuration and/or dimension so as to provide parts having such strength as to enable them to withstand the shocks normally encountered in autoloading.

Cognate subject matter not claimed herein is embraced in my Patent #2,945,423 dated July 19, 1960, of which this application is a continuation-in-part.

The action of the firearm of this invention is accomplished without the usual multiplicity of associated component parts familiar in firearms of the type herein contemplated.

The concept of the firearm hereof has been developed with attendant manufacturing problems being kept fully in mind and with particular regard'to the possibility of producing many of the component parts hereof as riveted or welding stampings, screw machine parts, or fabrications made by like systems of low cost manufacture, liberal tolerances being permitted practically throughout the structure so as to further aid in the economics of production.

It is a principal object hereof to provide a new and novel combination of components including 'a reciprocatory slide block and a pair of spaced action bars reciprocatory therewith and a breech block movable both longitudinally with the slide block and movable Vertically with respect thereto.

A very favorable weight ratio between slide block assembly and breech block is offered. That is, the hammer, hammer spring, scar and sear spring are mounted on and carried by the slide block instead of being on the trigger guard assembly, as is normally the case, and hence, said components serve to give additional weight to the slide block assembly, all to the end that a more favorable weight ratio between the operating shaft or rod and the breech block is offered.

A salient feature of the invention is in the provision of a T-shaped slide bloc-k disposed below a receiver and having cooperating action bars on opposite sides thereof which reciprocate along slots in and are supported by a donwwardly depending lug at the front end of the receiver. The T slot is in the lowermost portion of the receiver and the upper portion of the slide block is provided with a complemental T shape for reciprocation Within said T slot.

It is another chief object hereof to provide means for permitting considerable pretravel of the reciprocating slide block on the rearward movements thereof, before same contacts the breech block and carries same rearwardly therewith.

A still further object of the present invention is to provide a slide block assembly which may be actuated by action bars extending forwandly therefrom toward a suitable gas piston and spring assembly, the slide block assembly being suitably guided for reciprocation in the receiver, and the slide block and breech block each being provided with cooperating surfaces for the locking function during firing.

The invention further envisions an improved combination hammer and trigger action which provides a mechanism functioning as a buifer at the termination of the rearward or opening stroke having a capacity for absorbing the shock or blow attendant upon the abrupt stopping of the components at the termination of said rearward or opening stroke for the cocking of the hammer component preparatory to firing or refiring.

As another object hereof, I provide a novel combination of components including a hammer and sear and their related springs which are grouped with and supported by the slide block whereby the reciprocation of said components with the breech bolt is permitted.

A further object of this invention is to provide such other structural and operational improvements in mechanisms of the class to which reference has been made, as will hereinafter appear. For instance, by the use of a coin or equivalent object, the barrel and receiver assemblies may be quickly and easily removed from the stock, following which, all parts attached thereto, excepting the hammer and sear and related springs, may be readily disassembled Without the requirement for any further use of tools. By unscrewing an additional screw, the entire trigger guard assembly can be removed from the stock and all parts thereof easily disassembled without the requirement for any further use of tools. By unscrewing an additional screw, the entire trigger guard assembly can be removed from the stock and all parts thereof easily disassembled without tools.

Another purpose is to provide a new and useful means for attaching the action bars of a gas operated firearm to the gas piston and its related mechanism and to provide a combination piston bearing and spring guide rod, and a simple one-piece retaining detent which prevents said rod from loosening through repeated firing.

Additionally, it is an object hereof to provide a firearm action which will operate smoothly and with a relatively high .degree of freedom from the usual and normal malfunctions.

Further objects and advantages of the invention will become apparent as the following description proceeds, and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

It is to be appreciated that the utility and application of the construction hereof extend beyond any specific kind of firearm and comprehend the same new and useful features when incorporated in any other reasonably appropriate type of firearm.

In other words, the herein specific example of a physical embodiment of the invention is to be considered in all respects as being merely illustrative, all modifications and variations reasonably falling Within the meaning and range of equivalency of the disclosure hereof being intended to be embraced hereby.

Although a complete autoloading, bottom ejecting rifle, having a detachable side feeding box type magazine is shown, any of the component parts or groups of parts might find similar applications in other types of firearms, all within the spirit and scope of this invention.

Other objects and novel features of the invention will be more clearly and fully set forth in the following specification and the accompanying claims and will become more apparent from a study of the description in connection with the attached drawings wherein:

FIG. 1 is a broken top view of the firearm of the invention;

FIG. 2 is a broken side elevational view of the firearm shown in FIG. 1 with the action in the closed position;

FIG. 3 is a partial bottom plan View of the firearm shown in FIGS. 1 and 2 showing the bottom ejection port;

FIG. 4 is a partial longitudinal sectional view on the line 44 of FIG. 8;

FIG. 5 is a partial longitudinal sectional side elevational view showing the rear portion of the operating mechanism with the action in the open position;

FIG. 6 is a partial sectional view on the line 66 of FIG. 8;

FIG. 7 is a sectional view on the line 7-7 of FIG. 5;

FIG. 8 is a view similar to FIG. 5 with the action in the closed position;

FIG. 9 is a partial sectional view on the line 9-9 of FIG. 8;

FIG. 10 is a sectional view on the line 1010 of FIG. 8;

FIG. 11 is a view similar to FIG. 10 on the line 11--11 of FIG. 8;

FIG. 12A is a partial sectional view on the line 1212 of FIG. 13 showing one system of attaching a fore-end cover to the barrel;

FIG. 12B is a partial sectional view on the line 12-12 of FIG. 13 showing another system of attaching the fore-- end cover to the barrel;

FIG. 13 is a partial longitudinal sectional view of the firearm forward of the breech block and bedding plate;

FIG. 14 is a sectional view on the line 14-14 of FIG. 13;

FIG. 15 is a view similar to FIG. 14 on the line 1515 of FIG. 13;

FIG. 16 is a perspective view of the front end portion only of the right hand action bar;

FIG. 17 is a sectional view on the line 17-17 of FIG. 13 showing the action bars, the action bar clip, the recoil springs, the guide block, the block, detent clip, and the guide rod;

FIG. 18 is a perspective view of an action bar clip of the invention as made from a stamping;

FIG. 19 is a perspective view of an action bar clip of the invention, similar to the action bar clip of FIG. 18 but made from a bar of solid stock as contrasted with a stamping;

FIG. 20 is an enlarged sectional elevational view of the operating handle pivot and associated components shown in FIG. 8;

FIG. 21 is a perspective view showing a receiver, a portion of a slide block, a pair of action bars and a front bedding plate, for purposes of illustrating certain features of the invention; and

FIG. 22 is a sectional view on the line 22-22 of FIG. 21.

In the following description and claims, various details will be identified by specific names for purposes of convenience. These names, however, are intended to be as generic in their application as the art will permit.

Referring to the drawings by characters of reference, it will be seen that the illustrated firearm, as shown in FIGS. 1-3 discloses the general outline of the weapon as comprising a stock 2, stock butt 3, fore-end cover 4, barrel 6, rear cap 8, receiver 10, front sight 12, rear sight 14, magazine 16, magazine catch 18, operating handle 20, trigger 21, safety 22, trigger guard 24, front bedding screw 26, rear guard screw 28, front bedding plate 30, buffer plate 32, and stock plate 34.

The magazine is disposed on the right side of the firearm, though it might equally well be disposed on the left side thereof.

Receiver 10 is preferentially round in cross section, although it might be rectangular or irregular in cross section.

An opening on the upper side of receiver 10 is a mags. zine cut which functions to receive the upper end portion of magazine 16.

The bottom side of receiver 10 is cut away, and the interior thereof is hollowed, as is conventional.

The rearmost extremity of receiver 10 is provided with an annular tongue 36 receivable in a circumadjacent groove in the vertically and upwardly extending portion of a buffer plate 32 to prevent any spreading of the open bottom portion of receiver 10 following assembly. See FIG. 8.

A rear cap 8 is threadedly engageable, through the opening in the buffer plate, with the rearward end of the receiver. Said rear cap is one of two means serving to hold the receiver barrel and slide block assemblies relative to the stock.

Rear cap 8 is provided with a plurality of detent cuts 37 circumferentially arranged on the outer periphery theerof. See FIGS. 8 and 11.

A rear cap detent 40, in the form of a unitary, spring member, is generally triangular in shape and has one end portion seated in a centrally-disposed, verticallyextending, opening in buffer plate 32 and an opposite end portion seated in a centrally-disposed horizontally-extending opening in the buffer plate. The top of the buffer plate has a vertically extending slot for permitting the detent to be depressed downwardly, the detent being retained therewithin by its own spring tension. The detent serves as a click detent in detent cuts 37 on rear cap 8 for preventing loosening thereof due to autoloading firing. Detent 40 is capable of assembly and disassembly from buffer plate 32.

The trigger-hammer mechanism is essentially the equivalent of the mechanism shown and described by me in my Patent #2,945,422, dated July 19, 1960.

The lower extremity of buffer plate 32 is provided with a horizontally and forwardly-extending portion and a pair of spaced parallel vertically extending wing-like side walls 31 extending upwardly therefrom and forwardly of the aforementioned upper vertically-extending portion. See FIGS. 8 and 11.

A buffer plate bolt 3 extends through butt 3 and is threadedly engageable with buffer plate 32 whereby said buifer plate is held firmly against the L-shaped bedding surface provided on the upper inner wall of the stock. See FIGS. 5 and 8.

The rear extremities of trigger guard 24, stock plate 34, and the trigger housing shortly to be described, are disposed one above another. See FIG. 8. They are secured relative to the underside of the stock by means of a rear guard screw 28 threadedly engageable with buffer plate 32 for assisting in the securement of same relative to the stock. A front guard screw 50 secures the forward extremity of trigger guard 24 to stock plate 34 and the trigger housing disposed thereabove.

The said trigger housing includes a pair of transverselyspaced vertically-extending side Walls 42 connected together by a lowermost transverse horizontally-extending bottom wall 41 which may be of double thickness as at 54 in FIG. 5 at its forward and rearward ends whereby the screws 28 and 50 may be suitably engaged therewith.

Trigger 21 is an irregularly-shaped member having a lowermost downwardly-depending finger-engageable portion of conventional configuration and a vertically-extending bifurcated portion projecting upwardly therefrom and providing a pair of spaced ears 21 which extend upwardly through suitably aligned slots in the bottom wall of the trigger housing and the stock plate in such manner that each ear is disposed adjacent a side wall 42 of the trigger housing.

Trigger 21 is pivotally mounted relative to the trigger housing by means of a pair of trigger pivot pins 58, each being engageable with and extending through aligned openings in one of said ears and its adjacent side wall 42.

A generally U-shaped, elongated, connector 62 has spaced parallel upwardly extending side wals connected by a lower horizontally disposed bottom wall in the rearward portion thereof and a rear extremity receivable within the slot of the trigger so as to be disposed between the spaced ears thereof.

Connector 62 is also provided with a downwardly-depending lug portion 63- having a laterally-disposed rightangular slot 65 therethrough. The upper face of said lug portion is provided with an inclining-declining connector ramp or cam surface 66.

A connector pin 60' extends transversely through slot 65 and appropriately-aligned transverse openings in the ears of the trigger with opposite ends thereof abutting the side walls of the trigger housing, whereby the pin is held in situ.

The connector reciprocates forwardly and rearwardly along its horizontal axis and along its vertical axis upwardly and downwardly within the limits determined by pin 60 in slot 65.

As shown in FIG. 5, pin 60 is disposed at the bottom of the vertically extending portion of slot 65 wherefor the connector will be understood to have assumed the topmost position on its own vertical axis.

A generally U-shaped unitary safety-trigger-connector spring 68 includes a pair of spaced side portions disposed adjacent opposite outer sides of the trigger housing and a transverse midsection at the forward end thereof connecting therebetween. Said side portions have loops intermediate their ends engageable over the outer ends of the adjacent trigger pivot pins 58. Said transverse midsection passes beneath connector 62 to serve to push upwardly and forwardly against a lug 67 depending downwardly from connector 62 to hold the front end of the connector against the underside of the action bars 94. See FIGS. and 8.

The rear end of one side of spring 68 is in the form of a U having a forward free end receivable in a suitable opening in trigger 21 to hold the trigger normally under a forward tension for the Well known forward ready-to-fire position.

The rear end of the opposite side of spring 68 is bent transversely inwardly to provide an upward tension as a safety-detent spring.

Safety 22 is pivoted on a safety pivot pin 56 extending transversely therethrough and Supported at its opposite ends by the trigger housing side walls.

A transverse opening through safety 22 has on its upper wall a pair of detent notches, namely a forward detent notch 23 and a rearward detent notch 23.

The said rear end portion on one side of the safetytrigger-connector spring functions as a safety-detent spring by engagement in one or the other of said detent notches. When the spring is in the forward detent notch 23, it holds the safety in its oii position and when in the rearward :detent notch 23', it holds the safety in its o-n" position.

Lowermost sections of the side portions of the safetytrigger-connector spring bear on the opposite sides of the upper portion of the upper wall of the stock plate 34, as shown.

The safety mechanism functions to prevent inadvertent trigger operation when the firearm is loaded and cocked. The safety is pivoted to the trigger housing rearwardly of and in alignment with the trigger and is movable between a position of locked engagement with the trigger for preventing rearward movement thereof and a position of unlocked engagement with the trigger for permitting rearward movement thereof upon the firing of the gun. The trigger guard is slotted at its rearward portion to permit the safety to travel forwardly and rearwardly therethrough.

A hammer 70 is mounted on a hammer pivot pin 71 extending through and supported by a pair of spaced action bars 94 and 94 and a slide block 92 disposed therebetween. The rear face of the slide block is slotted to receive said hammer. The hammer is mounted for pivotal movement between a rearward cock position and a forward fire position.

The hammer is held under the tension of a U-shaped mousetrap or torsion type hammer spring 72 looped around the hammer pivot pin 71 on opposite sides of the hammer with the spaced opposite lower free ends 5 thereof bearing against the bottom surface of slide block 92. The transversely extendingmidsection bears against the rearmost face of the hammer so that the spring biases the hammer from cock to fire position upon the-release thereof.

A sear 75 is pivotally mounted on a sear pin 78 extending laterally through slide block 92 and is retained in situ by the front ends of hammer spring 72. See FIG. 10. The sear holds the hammer in the cock position and prevents the swing or throw thereof until released by the actuation of the trigger.

The sear is provided with an uppermost hammerengaging point 76 engageable in a complemental and mating searengaging notch in the hammer. The hammer is held relative to the sear through the hammer-engaging point which engages the sear-engaging notch of the hammer by virtue of the tension exerted by a sear spring 80 nesting in an opening in the slide block. The scar spring exerts a normally downward or outward pressure against the sear.

As the connector is pulled rearwardly upon rearward movement of the trigger, the sear is moved clockwise and the sear spring is compressed inwardly into its opening in the slide block whereby the hammer-engaging point of the sear is released from engagement with the sear-engaging notch in the hammer to fall and discharge the firearm.

The action bars and slide block and the hammer and sear and their related components may be manually or automatically actuated rearwardly.

As they are so rearwardly moved, tail 74 of hammer 70 passes between the side walls of the connector. Continuing rearwardly, the hammer is pivoted as tail 74 contacts the lower forward end of buffer plate 32 whereby the upper portion of the hammer is receivable between the spaced side walls 31 of the bulfer plate. See FIG. 5. In this manner, the hammer is actuated to the cock position. Immediately the hammer has reached full cock position, a portion 74' on the rearward face of the hammer strikes the bulfer plate 32 whereby the cocking action becomes increasingly difficult or hard and the operating mechanism is slowed down accordingly.

The front faces of side walls 31 of buifer plate 32 serve as stops for receiving the abutting rear end of the slide block at the termination of the rearward stroke.

When the hammer is pivoted into the full cock position, the sear point, under the tension of the sear spring, moves into the sear notch in the hammer.

The hammer is allowed a slight overtravel to a position beyond the full cock position so as to make a slight gap between the sear point and the sear notch before the rear end of the mechanism abuts the buffer plate so as to bring the components to a full stop at the limit of the rearward stroke. Such limit is determined by the abutment of the rear face of the slide block against the buffer plate. See FIG. 5.

The cooking of the hammer against the hammer spring functions as a buffer and brings the hammer, slide block, breech block and attached mechanism to a slow stop, all to the end that jarring is minimized.

When the operator cocks the firearm manually, he cocks only on the easy portion of the stroke. 011 the hard or difficult portion of the stroke, where the hard cocking portion on the hammer contacts the contacting surface of the buffer plate, it is not necessary for the operator to overcome the additional force encountered, the recoil mechanism accomplishing this automatically whereby the butter eifect is obtained. Such feature justifies the overtravel of the sear in that the sear has rnoved past the sear notch on the hammer before the hard portion of the stroke is reached.

When the slide block and attached mechanism are moved forwardly by the recoil springs, in the loading and closing of the firearm, the hammer, under tension of the hammer spring, pivots slightly forwardly on the 7 hammer pivot pin until the sear notch of the hammer contacts the sear point of the sear.

The hammer remains in this full cock position until released by the trigger at the completion of its cycle.

The connector is movable rearwardly from what will be referred to as its upper and forward position, shown in FIG. 8, by means of connector pin 60 fixed to the trigger. As the trigger is actuated rearwardly, pin 60 is swung rearwardly wherefore the connector is moved rearwardly.

As the slide block assembly moves forwardly, the hammer tail rides on ramp 66 wherefore connector 62 is cammed downwardly against the upward and forward pressure of the safety-trigger-connector spring at the forward end of said spring at its point of engagement with the connector.

The connector is fixed to the trigger by means of trigger pin 60 in slot 65 and the connector moves forwardly when the ramp thereof is sufiiciently depressed so as to free the connector pin from the vertical portion into the horizontal portion of the slot whereupon the safetytrigger-connector spring urges the connector forwardly by the transverse portion thereof acting on lug 67.

The connector is stopped in its forward travel when the forward face of lug 63 abuts the lower transverse wall in the slot in the bottom wall of the trigger housing.

At this point, the connector pin contacts, or nearly contacts, the rearward end of the horizontal portion of the angular slot.

When the trigger is released, pressure of the rear end of the safety-trigger-connector spring forces the trigger forwardly.

The connector pin, held snugly in the trigger, moves forward with the trigger along the horizontal portion of the angular slot until stopped by the front end of the slot.

As the connector is under the upward, as well as the forward, tension of the safety-trigger-connector spring, the rear of the connector pivots upwardly and the connector pin moves into the lower portion of the slot to the position shown in FIG. 8.

Inasmuch as the firearm hereof is of the side-loading, bottom-ejecting type, the forward extremity of connector 62 is split to premit the cartridge or shell to be ejected outwardly therethrough and out through the bottom of the firearm.

The lower portion of sear 75 is split in the form of an inverted T, each end of which is contacted by the connector, when the trigger is pulled to discharge the firearm. See FIG. 10.

Each side of the front of connector 62 has an upwardly extending portion which carries a connector hook 64, engageable in a mating notch in sear 75. As the trigger is pulled, the hook of the connector is locked vertically into the sear, thereby eliminating any possibility of the connector slipping downwardly off the sear. See FIGS. and 8.

The slide block 92 is centrally hung between a pair of laterally-spaced, parallel, action bars 94 (see FIGS. 8 and 9) which are attached to the slide block as by soldering, brazing, riveting, or equivalent means. Said action bars 94 are slidable in their respective complmental slots 31 extending inwardly from the opposite side faces of the front bedding plate 30. See FIGS. 7 and 22.

The upwardly extending rear end portion 98 of the slide block '92 supports the rearward extremity of a breech block 99. See FIGS. 8 and 10. Said breech block is of a configuration and dimension complementary to the inside of the receiver 10 and is reciprocal relative thereto.

The rear upwardly extending end portion 98 of the slide block 92 is generally T-shaped and is accommodated in a complementary T-shaped slot 102 in the receiver 10. See FIG. 10. This feature effectively prevents lateral and vertical movements of the slide block but nonetheless allows sufficient clearance to permit the slide block to reciprocate freely within the receiver.

In FIG. 13, a downwardly depending support block 400 is shown as being soldered, brazed or otherwise attached to the barrel 6.

A gas vent 402 may be drilled through the support block 400 for communication with an aligned opening 404 through the lower portion of the barrel 6.

A screw plug 406 is receivable in the lower portion of the gas vent 402 to seal off same.

A hollowed guide block 410 is provided having an integral cylindrically shaped forward end portion 412 which functions as a gas piston. Said portion 412 has a longitudinally extending horizontally disposed bore through which the forward end of a guide rod 420 extends whereby the guide block 410 slides freely relative to the guide rod 420.

A compressible detent spring clip 422 fits into a transversely extending slot through the forward end of the guide rod 420. See FIG. 13. Clip 422 is a unitary structure and is formed from spring wire or equivalent material. Upon assembly, it is compressible so as to be receivable in the slot of the guide rod 420 and to be held therein and relative thereto by its own spring tension.

The forward extremities of the action bars 94 and 94 are rounded and are reduced in thickness, as best shown in FIG. 16, for receipt in correspondingly rounded slots in the guide block 410. The inner sides of the action bars are slotted at 94 slightly rearwardly of the for ward ends thereof so as to receive the action bar clip now to be described.

Longitudinal movement between action bars 94 and the guide block 410 is prevented by the action bar clip, generally designated by 430 in FIG. 19 and by 430' in the modified form shown in FIG. 18.

The action bar clip comprises a pair of spaced vertically extending side wall members 432 connected together by a transverse bottom wall member 434.

In the modified form of FIG. 18, the side walls are designated as 432' and the bottom wall as 434'.

Side walls 432 are receivable in the appropriately aligned slots 94' on the inner sides of action bars 94 and slots in the guide block 410 whereby longitudinal movement between the action bars 94 and the guide block 410 is prevented.

Vertical movement is prevented as the rounded end portions of the action bars are receivable in corresponding circular grooves in the guide block 410.

The action bars are maintained in parallel spaced relationship as to each other by means of the slide block at the rear extremities thereof and by the guide block at the forward extremities thereof.

On assembly of the guide block 410 and action bars 94, the forward ends of the action bars are pushed forwardly into the appropriate mating slots in the guide block.

The action bar clip is embraced around the guide block with the upper inwardly extending ears 436 in FIG. 19 (and 436 in FIG. 18) engaging the top of the guide block 410, :as best shown in FIG. 14.

The inward spring tension of the action bar clip insures a tight fit thereof around the guide block.

When the action bars are assembled into the guide block, the slots in the action bars as aligned with the slots in the guide block wherefor the side walls of the action bar clip can be pushed into and through the slots.

The tapered ears 436 of the action bar clip provide camming surfaces to cause the side wall members of the action bar clip to spring outwardly as they are pushed into the assembled position.

With the action bar clip pushed upwardly to its limit, the ears snap inwardly under a spring tension provided by the transverse bottom wall 434 and are held thereat.

To disassemble, ears 436 may be manually pried out- I 9 wardly by ones fingers so as to release the cars from their mating engagement with the top of the guide block. The lower wall of the action bar clip may then be manually engaged so as to be downwardly withdrawn.

A recoil spring comprises a small diameter spring 440 which is wound right hand (or left hand if desired) and a large diameter spring 442 which is wound opposite from the winding of the small diameter spring. By means of the two springs, a spring action more nearly like that of a spring which is longer than space permits in this instance is achieved.

By means hereof, I obtain a softer spring action and a more desirable scale to the spring while keeping down the fiber stress as is well known.

To assemble the springs into the firearm, the action is placed in the closed position.

Guide rod 420' is pushed through the support block 409 and the guide block 410.

Guide rod 420 is moved slightly rearwardly and springs 440 and 442, assembled one inside the other, are pushed forwardly on the guide rod, the feeding being from the rear end of the guide rod.

With the springs on the guide rod, the guide rod may be screwed into the front bedding plate 30.

The guide rod is screwed into plate 31 until detent spring clip 422 is brought into engagement with the plurality of radially disposed detent cuts or slots 444 in the forward face of the support block 400 in the conventional manner.

The slots 444 may comprise U shaped or if desired cone or cup shaped recesses of suitable depth so as to receive the end of the spring clip 422.

The forwardly facing wall of the piston 412, around the guide rod 429, is provided with an annular concaved ring providing a pair of sharp edges Which function as scrapers and assist in keeping the guide rod and the inside wall of the cylinder free of carbon and fouling accumulation.

An annular portion of the guide block 410 immediately to the rear of the piston 412 is concaved so as to act as a gas deflector and to deflect gases forwardly when the piston leaves the cylinder during the operation of the firearm.

In operation, after the cartridge is fired, the gun functions by a means now to be described. After the bullet passes the aligned gas vent openings 404 and 402, gas passes from the barrel therethrough under high pressure to the piston chamber and strikes the piston head 4-12 with a sharp blow, as is conventional, to the end that the recoil energy of the discharge of the firearm is transmitted to the piston and recoil springs.

After the inertia of the slide block assembly has been overcome, movement of said assembly rearwardly is initiated. The assembly will be understood to include the guide block 419, action bar clip 430, action bars 94, slide block 92, hammer 70, hammer pivot pin 71, hammer spring 72, sear 75, sear spring 80', sear pin 78, operating handle 20, operating handle retaining plunger 113, operating handle retaining spring 114, and operating handle pivot 116.

The slide block assembly initially travels a relatively short distance, identified herein as the pre-travel. In the design of the firearm, I have provided for as much as 0.5" pre-travel. The pre-travel distance may be varied or controlled during manufacture as desired. This offers the bullet an opportunity to have left the muzzle whereby the chamber pressure is sufi'iciently reduced so as to facilitate easy extraction.

Following the pre-travel, the cam face 118 of the slide block 92 contacts the cam face 120 of the breech block 99 and forces the front end 122 of the breech block 99 downwardly thereby causing the locking lug surface 124 of the breech block 99 to become disengaged from the mating locking surface of the receiver 10.

The slide block assembly then travels rearwardly in the conventional manner by means of the force imparted 45 FIG. 20.

10 to the front end of the piston 412 by the gas resulting from the explosion of the cartridge.

The weight of the slide block assembly is greater than the weight of the breech block thereby enabling the former to hold its momentum as it carries the latter rearwardly with it.

During this period of rearward travel, the cartridge is ejected by the ejector 127 and the hammer 70 is cocked by means of the hammer tail 74 striking the buffer plate 32.

The recoil springs have meantime been compressed. During its forward travel, by means of the recoil springs releasing their tension, the breech block 99 picks up a cartridge from the magazine 16 and retains the rear end thereof by means of the rim retainer 128 and feeds it into the chamber 131 of the barrel 6.

When the breech block 99 reaches its forwardmost position, the lower surface 132 of the breech block strikes the aligned surfaces 134 of the receiver 10 and barrel 6.

When the firearm is fully closed, the upper supporting surface 136 of the slide block 92 contacts a complementary lower supporting surface of the breech block and retains the front end of the breech block in the locked position. See FIG. 8.

It is to be here appreciated that it will be impossible to discharge the firearm until the breech is fully closed and locked. When the hammer is down in the fired posi tion, shown in FIG. 8, the forward face of the hammer strikes the rear vertically slotted portion of the slide block.

The vertically slotted portion of the slide block of course starts to move rearwardly as the slide block per se moves to the rear thus making any contact of the hammer face with the firing pin impossible until the slide block is again in its forwardmost position.

The rear of the slide block is slidably retained in the lower portion of the receiver in the aforedescribed T slot.

The operating handle is attached to the operating handle pivot 116 by means of welding, brazing or equivalent means. If desired, the handle and pivot could be made as one piece.

The pivot 116 is provided with a flat portion 142 that is contacted by the fiat bottom surface 144 of the operating handle retaining plunger 113 under the spring pressure of the operating handle retaining spring 114. See In this manner, the operating handle 29 is retained in the slide block 92. See FIGS. 5, 8, 9 and 20.

To remove the operating handle 20 from the slide block 92, when the slide block assembly is removed from the stock 2, it is only necessary to rotate the operating handle 20 in either direction. The flat portion 142 cams the operating handle retaining plunger 113 upwardly to allow the operating handle 20 to be withdrawn from the slide block 92.

It may be reassembled by pushing the operating handle retaining plunger 113, containing the spring, into the opening 146 in the slide block 92 with a nail or the like. When the plunger is fully seated, the operating handle may be pushed in place and the nail withdrawn.

If desired, the front end 148 of the firing pin 150 may 0 also be used as the assembly pin.

The fiat bottom surface 144 of the operating handle retaining plunger 113 contacting the flat portion 142 of the operating handle pivot 116 under the pressure of the operating handle retaining spring 114 will keep the operating handle in a vertical position, all as shown in FIG. 9.

sure of the recoil springs 440 and 442. Bya sidewise 11 push in the opposite direction from which it was set in the notch, the operating handle will snap out of the notch and the breech will close by the action of the recoil springs.

The receiver, barrel, and slide block assembly are held relative to the stock only at two points, first, by the rear cap 8 threadedly engaged at the rear end of the receiver 10 through the buffer plate 32, and second, by the front bedding screw 26 which is engageable with the front bedding plate 30 so as to hold same securely relative to and on the front bedding surface of the stock 2, and with said bedding plate being held onto the receiver by the barrel thread, as shown in FIGS. and 8.

Side motion of the front of the receiver in the stock 2 is prevented by the snug fit of the sides 156 of the stock 2' with the sides 157 of the front bedding plate 30, as shown in FIG. 7.

The front bedding plate 30 and the buffer plate 32 'are the only contact points of the barrel and receiver assembly with the stock.

The assembled double action bars occupy a wider space in the stock than is occupied by the barrel forwardly of the chamber. Viewed from the top, an unsightly gap remains, and is concealed from view by a unitary fore end cover 4 made from plastic or other suitable material. See FIGS. 5, 8, 12A, 12B and 13.

A semicircular tongue 158 fits into a complemental groove 160 in the front bedding plate 30. A pair of downwardly depending clips 162A or 162B at the extreme front end of the fore end cover 4 serve as spring snaps and hold the bottom surface 164 of the fore end cover 4 firmly against the top surface 166 of the stock 2.. The spring tension of the clips 162A or 162B is provided by the inherent flexibility of the material from which they are made.

Forward movement of the fore end cover 4 is prevented by the extreme front end of the clip contacting the inner stock surface 411 immediately forward of the front end of the square portion of the guide block 410, with the action in the closed position. See FIG. 17.

The form of clip, one half of which is shown as 162A in FIG. 12A, snaps over the barrel 6 to retain the fore end cover 4 in place. However, if it is desired to keep the barrel completely free floating in the forward portion of the stock, the clip, one half of which is shown as 162B in FIG. 12B, snaps into corresponding grooves 168 cut in the inner forward portion of the stock 2.

When the firearm is being carried loaded and cocked, and with the safety in the off position, one may inadvertently place his fingers in the ejection port on the bottom of the firearm. If his fingers were able to contact the sear or a protruding portion of the connector, he might accidentally discharge the firearm. To prevent same, the sear is protected by the overhang of the rear lower portion 170 of the slide block 9 2, which will, owing 12 to the narrow ejection slot, prevent the fingers from contacting the sear 75.

An upwardly extending portion 174 of the stock plate 34 protects the downward depending portion 67 of the connector 62 from accidental contact by the fingers.

What it is desired to claim and secure by Letters Patent of the United States is:

1. In a gun, the improvement comprising, a receiver having a longitudinally-extending T slot opening through the lower surface thereof, a slide block supported below and reciprocable relative to said receiver and having an upwardly extending T-shaped support portion complemental to and slidable within the T slot of said receiver, a pair of laterally spaced action bars supported below said receiver and having rearward end portions fixed to opposite sides of said slide block and being reciprocable therewith, and a bedding plate engageable with and depending downwardly from said receiver forwardly of said slide block and having a pair of laterally spaced slots for receiving and supporting said pair of action bars forwardly of the rearward end portions thereof as they move rectilinearly forwardly and rearwardly.

2. In the gun as set forth in claim 1, including a barrel, a support block fixed to the forward end of said barrel and having a gas vent extending therefrom and communicating with the bore of said barrel, a guide rod suspended below said barrel by said bedding plate and support block, and a guide block reciprocable along said guide rod between said bedding plate and support block, said pair of action bars being fixed to said guide block.

3. In a gun as described in claim 2 including, a unitary self-retained fore end cover.

4. In a gun as described in claim 2 including, a unitary self-retained action bar clip.

5. In a gun as set forth in claim 1, including, a barrel, a support block fixed to the forward end of said barrel, a guide rod suspended from said barrel by said bedding plate and support block, a guide block reciprocable along said guide rod between said bedding plate and support block, said pair of action bars being fixed to said slide block at the rear ends thereof and to said guide block at the forward ends thereof, a unitary self retaining detent spring clip at the forward end of said guide rod, and spaced detents in the forward end of said support block for precluding rotation of said guide rod.

References Cited in the file of this patent UNITED STATES PATENTS 1,441,807 Horan Ian. 9, 1923 2,615,370 Koucky Oct. 28, 1952 2,674,822 Studler Apr. 13, 1954 2,685,754 Crittendon et al Aug. 10, 1954 2,825,170 Simmons Mar. 4, 1958 

